Hmm...
I've tried a KK and that's a fleece outer, but it's more of an AIO. It worked pretty good but by morning she was a little damp, it's better for her day sleeps.
I used fleece pockets o/night on the girls for ages and never had problems but they weren't having 3 or 4 feeds o/night.
I haven't seen a Bettlebums irl, I've heard fabulous things about them though....there are only on ozebaby right?
I just love the o/night ones we have atm but they do take a while to dry, which for here in the sunshine is fine but when travelling I might not have that option.
I think I'll go foraging around my sewing box and see what I can come up with.